This study will invoke a new perspective to the empirical analysis of classificatory systems called the prototype model. The methodology associated with the prototype model will be used to analyze the DSM-III classification of personality disorders. There are two stages in this study. Stage I will be a feasibility study to test the applicability of the prototype model to the classification of the personality disorders. Stage II intends to formulate a revised classification of personality disorders. Funding is only being requested at this time for Stage I of the research. The research in Stage I has two parts. In Part A, the focus will be on the identification of exemplar prototypes for the various personality disorders. There are six studies in Part A: (A.1) creating a pool of case histories, (A.2) identification of exemplars from the case histories, (A.3) verification of exemplars, (A.4) comparing exemplars to non-exemplars, (A.5) predicting exemplars among revised case histories, and (A.6) testing for possible sex bias in assigning personality disorder diagnoses. Part B will use an "act frequency" approach to general objective characteristics that can be used in the diagnostic criteria for defining the personality disorders. Part B will contain seven studies: (B.1) face validity of the DSM-III-R criteria, (B.2) preliminary study of objective vs. subjective personality traits, (B.3) subjectivity vs. objectivity of the DSM-III-R criteria, (B.4) generating acts, (B.5) prototypicality ratings of acts, (B.6) comparing acts to DSM-III-R criteria, and (B.7) cross-validation of acts. Two groups of subjects will be used in this study. The first will be a group of general psychiatrists, randomly sampled from the membership of the American Psychiatric Association. The second will be a group of research psychiatrists, all of whom have published articles/books/chapters on the topic of the personality disorders. Throughout this research endeavor, two general goals will be paramount: (1) gathering information which could be used to improve the classification of the personality disorders and (2) testing the utility of the prototype perspective for understanding the classification of psychopathology.